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16th IEEE Latin American Symposium on Circuits and Systems, LASCAS 2025

作者： Oliveira, Luiz H. N. Amaral, Wellington A. Haddad, Sandro A. P. Munoz, Daniel M. Barcelos, Eduardo A. Sotero, Vinicius V. M. Jonhson, Emmanuel K. M. Campagnucci, Pamela R. A. N. Lima, Luis V. N. Electronics Engineering Undergraduate Program Faculty of Gama Brazil Mechatronics Graduate Program University of Brasilia Faculty of Technology Department of Mechanical Engineering DF Brasilia Brazil

ISBN: (纸本)9798331522124

The demand for efficient power management solutions in electronic devices has increased significantly, especially for microcontrollers operating in low-power modes. This article presents the design and implementation of a Pulse Frequency Modulation (PFM)-based buck converter for applications in 32-bit microcontrollers using 22nm CMOS technology. The methodology involves the development of a Constant On Time (COT) architecture that maintains a fixed duration for the activation of the high-side MOSFET, using a monostable multivibrator to generate the necessary timing signals. The converter's performance was simulated under various load conditions and process corners to evaluate its efficiency and output characteristics. The results show that the proposed buck converter achieves high efficiency, with peak values above 95%, while maintaining a low output ripple. Specifically, the converter exhibits an efficiency of 93.4% at a load of 1mA, with output ripple voltages as low as 2.20 mV under ideal conditions. The contributions of this work lie in the advancement of PFM converter technology for modern microcontroller applications, demonstrating the potential of 22nm CMOS processes to improve power efficiency and performance. © 2025 IEEE.

关键词： CMOS integrated circuits

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Utilizing Mobile Robots to Teach Dengue and Chikungunya Prevention in Brazilian Schools

Utilizing Mobile Robots to Teach Dengue and Chikungunya Prev...

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2024 Brazilian Symposium on Robotics (SBR), and 2024 Workshop on Robotics in Education (WRE)

作者： R. B. Costa Pedro H. L. Gomes Luiz F. Rodriguez Silva M. A. Pastrana Maria C. C. Gontijo M. S. Luiz Daniel M. Muñoz Faculty of Gama Aerospace Engineering Undergraduate Program University of Brasilia Brasilia DF Brazil Faculty of Gama Electronics Engineering Undergraduate Program Department of Mechanical Engineering Mechatronics Graduate Program

ISBN: (数字)9798350391084

ISBN: (纸本)9798350391091

This paper introduces a novel approach to combating the spread of Dengue and Chikungunya, two prevalent arboviruses in tropical regions, especially in Brazil. The research presents a low-cost differential topology robot designed as an educational tool to raise awareness about mosquito breeding grounds among students and teachers in public schools across the Federal District, Brazil. Developed at the University of Brasilia, the robot is deployed in collaboration with the Federal District Health Department to support prevention campaigns in schools. The paper evaluates the effectiveness of this innovative tool in enhancing community engagement and improving health outcomes. The findings suggest that integrating robotics into health education can significantly elevate awareness and strengthen prevention strategies against arboviral diseases.

关键词： Pediatrics Prevention and mitigation Education Collaboration Robot sensing systems Topology Public healthcare Robots Viruses (medical) Diseases

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Whale Optimization Algorithm for structural damage detection, localization, and quantification

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Discover Civil engineering 2024年第1期1卷 1-22页

作者： Monteiro, Daniele Kauctz Miguel, Letícia Fleck Fadel Zeni, Gustavo Becker, Tiago de Andrade, Giovanni Souza de Barros, Rodrigo Rodrigues Graduate Program in Civil Engineering (PPGEC) Federal University of Rio Grande Do Sul (UFRGS) Porto Alegre Brazil Department of Mechanical Engineering (DEMEC) Graduate Program in Mechanical Engineering (PROMEC) Graduate Program in Civil Engineering (PPGEC) Federal University of Rio Grande Do Sul (UFRGS) Porto Alegre Brazil Graduate Program in Mining Metallurgy and Materials Engineering (PPGEM) Federal University of Rio Grande Do Sul (UFRGS) Porto Alegre Brazil Department of Mechanical Engineering (DEMEC) Federal University of Rio Grande Do Sul (UFRGS) Porto Alegre Brazil Applied Mechanics Group (GMAp) School of Engineering Federal University of Rio Grande Do Sul (UFRGS) Porto Alegre Brazil

This paper introduces an approach for vibration-based damage detection based on matrix updating aided by the Whale Optimization Algorithm (WOA). The methodology uses the Data-driven Stochastic Subspace Identification (SSI-DATA) technique to determine the modal parameters, which are compared with those obtained from both healthy and damaged conditions of the structure. The methodology’s efficacy is assessed through three distinct steps: numerical simulations, experimental data, and real-world data from a bridge. Initially, numerical analyses are conducted on a cantilever beam, a 10-bar truss, and a Warren truss subjected to environmental vibrations with varying damage cases and noise levels. Subsequently, experimental validations are performed on a test system and in the Z24 Bridge. Results from the computational simulations demonstrate the method’s promise to identify, locate, and quantify single and multiple damage cases, even amidst signal noise, variations in the first vibration mode as minimal as 0.015%, and complex structures with 54 elements. Moreover, the matrix updating method utilizing WOA showcased superior accuracy compared to existing techniques in the literature. In addition, the Z24 Bridge example validated the capability of the presented damage detection method to localize structural damage solely based on natural frequencies.

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Numerical estimation of the coupling loss factor for L-joined plates 27

Numerical estimation of the coupling loss factor for L-joine...

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27th International Congress on Sound and Vibration, ICSV 2021

作者： Barbosa, Rangel Moura Medeiros, Eduardo Bauzer Graduate Program in Mechanical Engineering UFMG Belo Horizonte Brazil

ISBN: (纸本)9788378807995

Metallic panels are common in a variety of engineering applications. A configuration often found in vehicular applications can be conveniently described as L-joined Plates. The present work considers the vibration transmission between isotropic plates joined by means of an L-junction. The coupling loss factor (CLF), a parameter used in the statistical energy analysis (SEA) is studied in order to characterize the behavior of this configuration. Initially, this parameter is obtained by means of the wave approach. Subsequently, the finite element method (FEM) combined with an experimental statistical energy analysis model (ESEA), provides values of the apparent coupling loss factor (ACLF) for this system. Within the analysis, comparisons between the results of the approaches are established and the influence of the damping loss factor (DLF) and plate boundary conditions on the results are investigated. In the wave approach, it is confirmed that there is no influence of these mentioned factors, whereas in the procedure with FEM and ESEA the influences are observed. In the latter, the boundary conditions result in more significant changes of ACLF values at low frequencies, while for the higher damping values used it has been found that the results are closer to those of CLF in the wave approach. In general, the tendency of approximation between the results of the approaches is observed at higher frequencies. The present research also indicates that the ESEA results through FEM application are affected by the excitation. © "Advances in Acoustics, Noise and Vibration - 2021" Proceedings of the 27th International Congress on Sound and Vibration, ICSV 2021. All rights reserved.

关键词： Boundary conditions

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4e Analysis of the Thermal Power Plant of a Coke Integrated Steelmaking Process

SSRN

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SSRN 2023年

作者： Leal, Elisângela Martins Coura, Dimas Pereira Graduate Program in Mechanical Engineering Department of Mechanical Engineering School of Mining Federal University of Ouro Preto Brazil

The steelmaking industry in Brazil plays a vital role in the country's energy landscape, being a major electricity consumer. To remain globally competitive, the industry requires a strategic plan for efficient energy use, low environmental impact, and cost reduction. One promising approach is implementing thermoelectric power plants that utilize waste gases from steelmaking. This study analyzes the energy, exergy, environmental, and economic aspects of such a plant, considering green hydrogen addition achieved through water electrolysis using photovoltaic power. A computational model with Scilab is used, validated with data from a real thermal power plant. Computer simulations using different fuel mixtures show that adding up to 30% hydrogen to blast furnace gas achieves energy and exergy efficiency equivalent to the reference scenario (scenario zero) while reducing fuel costs. Effective energy management within organizations can lead to significant financial gains. The real operating model (scenario zero) exhibited a lower exergetic efficiency of 23.87%, highlighting the need for sustainable solutions. Embracing hydrogen-based technologies can pave the way for a greener, more energy-efficient future in Brazil. © 2023, The Authors. All rights reserved.

关键词： Economic analysis

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Integer programming Approaches to an Issue of Scheduling for a Truck-Drone Last-Mile Delivery System with Parcel Pickup Service 13

Integer Programming Approaches to an Issue of Scheduling for...

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Joint 13th International Conference on Soft Computing and Intelligent Systems and 25th International Symposium on Advanced Intelligent Systems, SCIS and ISIS 2024

作者： Yamada, Kotaro Karuno, Yoshiyuki Iima, Hitoshi Graduate School of Science and Technology Kyoto Institute of Technology Mechanodesign Program Kyoto Japan Kyoto Institute of Technology Faculty of Mechanical Engineering Kyoto Japan Kyoto Institute of Technology Faculty of Information and Human Sciences Kyoto Japan

ISBN: (纸本)9798350373332

In this paper, we consider a scheduling issue for parcel delivery and pickup services by a truck-drone last-mile delivery system. We are given a single carrier truck and multiple identical drones to serve a finite set of customers. The single carrier truck plays the role of a mobile depot for the drones, and it visits several stops in a given order of them. The given order of stops constitutes a fixed truck route, and the carrier truck is allowed to launch (resp., to retrieve) a drone to (resp., from) a customer at a stop. For each sortie of a drone, the launching stop and the retrieving stop must be the same. The load capacity of a drone is limited to one, and for a sortie of a drone at a stop, there are three options: (i) only deliver a parcel to a customer, (ii) only pick up a parcel from a customer, and (iii) deliver a parcel to a customer, and then pick up a parcel from a customer. The scheduling problem asks to find an assignment of customers to drones with sortie options and a choice of a truck stop for each sortie in the assignment. The objective is to minimize the total duration of the carrier truck over all the stops, which is equivalent to minimizing the makespan. In this paper, we first propose an extended integer program for the case with both delivery and pickup services from an existing one for the case with delivery service only. We also conduct numerical experiments to demonstrate the solution quality of the proposed integer program by utilizing an integer programming solver, and report the results. © 2024 IEEE.

关键词： Integer programming

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INFLUENCE OF TORREFACTION SEVERITY ON WOOD BLEND FROM AMAZONIAN RESIDUES 31st

INFLUENCE OF TORREFACTION SEVERITY ON WOOD BLEND FROM AMAZON...

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31st European Biomass Conference and Exhibition, EUBCE 2023

作者： Souto, Normando P. B. Chaves, Bruno S. Macedo, Lucélia A. Lamas, Giulia Cruz Barbosa, Thais de Rodrigues, Pedro Paulo O. Cardoso, Marcela Rodrigues Rousset, Patrick Silveira, Edgar A. Military Institute of Engineering Nuclear Engineering Graduate Program Rio de Janeiro Brazil Brasilia DF 70818-900 Brazil University of Brasília Mechanical Sciences Graduate Program Laboratory of Energy and Environment Brasilia-DF 70910-900 Brazil 73 Rue J. F. Breton Cedex 5 Montpellier34398 France

This study investigated and characterized the torrefaction treatment of Amazonian wood residues blend. Six wood residue materials from legal wood processing from the Jacundá National Forest (Rondônia, Brazil) were blended and torrefied at 225, 250 and 275 °C for 60min in an inert atmosphere (N2). The wood residues comprised Peltogyne lecointei (S1), Erisma uncinatum (S2), Martiodendron elatum (S3), Handroanthus incanus (S4), Dipteryx odorata (S5), and Allantoma decandra (S6). The solid yield (SY) and torrefaction severity index (TSI) were applied to evaluate the torrefaction process severity. The pyrolysis of torrefied biomass and chemical analysis (proximate, ultimate, and calorific) allowed to evaluate the influence of torrefaction severity on the blend. The preliminary results showed that torrefaction temperature highly affects the blended samples, with a weight loss of 4.9% for 225 °C and 34.96% for 275 °C torrefaction. A goodness of fit was achieved between the calculated TSI and volatile matter (R2 =0.99), fixed carbon (R2 =0.99), and ash contents (R2 =0.93). HHV showed an improvement of up to 7% for 275 °C torrefaction. The results provided valuable information to determine the process parameters for further torrefaction and pelletizing processes (TAP) aiming at fuel production in decentralized systems, reducing diesel dependence on the Amazon region. © 2023 ETA-Florence Renewable Energies.

关键词： Blending

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Learning from failure - Development of a Culture of Failure Scale for Higher Education

Learning from failure - Development of a Culture of Failure ...

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2022 IEEE IFEES World engineering Education Forum - Global engineering Deans Council, WEEF-GEDC 2022

作者： Malschutzky, Michael M. Gurganus, Jamie R. Department of Management Sciences Germany Mechanical Engineering and Graduate School University of Maryland Baltimore County Engineering and Computing Education Program Baltimore United States

ISBN: (纸本)9781665475280

Benefits of a failure friendly culture, e.g., learning from failure, are widely known in occupational settings. Validated scales have been developed to measure organizational failure culture and individuals' mind-sets on failure. While research on learning from failure exists in secondary education, scales for higher education are lacking. To support both higher education engineering instructors and students, this contribution aims to develop a Culture of Failure Scale to assess students' and lecturers' handling of failures in engineering higher education settings. This data-driven approach helps inform instructors about aspects of educational settings that are safe and conducive to learning and supports their students to develop a mind-set where failures are seen as a source for improvements and learning. Exemplary application of the developed scale is shown by assessing the failure culture in different groupings, e.g., gender, between two participating German and US institutions. © 2022 IEEE.

关键词： Failure (mechanical)

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Effect of Overload and Underload on Subsequent Deformation Behavior during Cyclic Deformation

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Zairyo/Journal of the Society of Materials Science, Japan 2022年第2期71卷 159-166页

作者： Kondou, Ryouji Yama, Katsunari Energy and Environmental Program School of Engineering Faculty of Engineering University of the Ryukyus Nishihara-cho Nakagami-gun Okinawa903-0213 Japan Department of Mechanical Systems Engineering Graduate School of Engineering and Science University of the Ryukyus Nishihara-cho Nakagami-gun Okinawa903-0213 Japan

A multi-scale analysis of elasto-plastic deformation and dislocation movement and accumulation of tricrystalline models during cyclic deformation was performed. The accumulation of dislocations in geometrically necessary dislocations (GNDs) and statistically stored dislocations (SSDs) was investigated in detail. Experimental observations have shown that fatigue life and fatigue crack propagation are also deteriorated when the material is subjected to overload or underload. However, in the microscopic and mesoscopic regions, where the effects of the crack tip shape change are not related to the size of the crack tip, a different phenomenon is essentially occurring. In this paper, the effects of overload and underload are investigated using a simple model without a crack. From the analysis results, it was found that the dislocation structure generated in the material subjected to overload or underload affects the subsequent deformation behavior. However, even though the absolute values are the same, the effects of overloading and underloading on the subsequent deformation are different, and underloading increases the non-uniformity of the subsequent deformation, which is on the dangerous side, while overloading decreases with increasing the number of repetitions. ©2022 The Society of Materials Science, Japan

关键词： Crack tips

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Design of a 3 Degree-of-Freedom Upper-Limb Active Exoskeleton with Cable-Driven Actuators for Neuromotor Rehabilitation 1

Design of a 3 Degree-of-Freedom Upper-Limb Active Exoskeleto...

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1st IEEE Colombian Caribbean Conference, C3 2023

作者： Dias, Eduardo Ulhoa, Pedro Andrade, Rafhael Universidade Federal Do Espírito Santo Department of Mechanical Engineering. Vitória Brazil Universidade Federal Do Espírito Santo Department of Electrical Engineering Vitória Brazil Universidade Federal Do Espírito Santo Graduate Program in Mechanical Engineering Vitória Brazil

ISBN: (纸本)9798350341799

Exoskeletons are wearable mechanisms which, parallel to the wearer's joints, modulate movements through active or passive torque application. While existing upper-limb exoskeletons offer benefits in strength augmentation and therapy, they often suffer from limited degrees of freedom and excessive bulk, hindering their utility in neuromotor rehabilitation. This study introduces a three degree-of-freedom active upper-limb exoskeleton optimized for neuromotor rehabilitation. Employing anthropometric data and rigorous kinematic analysis, the design accommodates elbow flexion/extension, forearm pronation/supination, and hand gripping. The upper limb dynamics, kinematics, and physiology were evaluated to provide adequate joint ranges of motion. Cable-driven actuators in the elbow and forearm joints were designed to provide low worn weight through the relocation of the motor units away from the user's joints. The result is a lightweight, compact exoskeleton that provides optimal conditions for neuromotor rehabilitation. Finally, a preliminary control strategy was tested using myoelectric signals to trigger motion. © 2023 IEEE.

关键词： Actuators

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